The judges disagreed with Slayton's arguments regarding police questioning, a recorded interview with his then-wife, the testimony of his then-ex-wife, and the evidence as a whole.

Slayton, 46, is serving a mandatory sentence of life without parole for first-degree premeditated murder in Gibson's Feb. 1, 1992, death. Testimony showed that Slayton strangled Gibson, a 39-year-old mother of five, with the passenger-side seat belt in his vehicle and then dumped her body in the parking lot next to the former Ewald's Bar on South Niagara in Old Town Saginaw.

Slayton argued that the conversation, in which Sandra Slayton participated knowingly and as an agent of the now-defunct Cold Case Homicide Unit of the Saginaw Police Department’s Violent Crime Task Force, violated his Fifth Amendment right against self-incrimination, his Sixth Amendment right to assistance of counsel, and two Michigan Department of Corrections prison rules.

The judges disagreed, noting that Miranda warnings notifying Slayton of his Fifth Amendment right were not necessary because the nature of the conversation between Slayton and his wife did not include “the coercive environment,” at least in Slayton's mind, “present in a traditional police interrogation.” Slayton's Sixth Amendment right was not violated, the judges wrote, because prosecutors had yet to charge Slayton with any crime when he spoke to his wife.

Slayton argued that the recorded conversation violated prison rules regarding eavesdropping and recorded conversations, but the judges disagreed, noting that only one party of a conversation has to consent to being recorded and that the prison administrators approved of the recording equipment being used.

Slayton also challenged the testimony of Rachelle Carpenter, his wife at the time of the homicide, who testified that she assumed Slayton was telling the truth when he said he killed Gibson. Slayton argued that his due process rights were by violated by Carpenter's testimony of her opinion on Slayton's guilt, but the judges wrote that she only was testifying regarding why she did not go to the police after Slayton's confession.

Slayton also argued that his attorney, Rodney O'Farrell, should have motioned for a mistrial because Carpenter made mention of previous domestic violence arrests, but the judges wrote that if O'Farrell had done so, it would have been moot because Saginaw County Circuit Judge Fred L. Borchard told the jury to disregard Carpenter's statement.

Finally, Slayton argued that county Assistant Prosecutor Paul Fehrman failed to prove that the murder was premeditated.

The judges noted that Slayton strangled Gibson, meaning he made her lose consciousness and continued to apply pressure until she died.

“Given the testimony regarding the time between unconsciousness and death, the jury could reasonably conclude that (Slayton) had enough time to consider his actions,” the judges wrote.